This invention relates to the method and apparatus for protecting alternating current circuits against excessive current flow.
In applications of alternating current circuits there is a requirement for a reliable, efficient and economical means for sensing alternating current levels or flow rates, and for protecting the alternating current circuit from damage in the event of short circuits caused by component failure or the low impedance presented by a saturated core of an AC circuit that has a transformer load which results from a repeated phase at turn on. The prior art discloses several apparatuses and methods for the protection of alternating current circuits. Among these are fuses, circuit breakers, precision current analog techniques and control transformer methods. In all of the above enumerated type devices, the main disadvantages have been inefficiency, unreliability, size and complexity.